As a matter of interest, Punch for January 14, 1887, has this parody of "King of the Cannibal Islands," about Arthur Balfour.

BALFOUR'S "IRREPRESSIBLE" DONKEY.

OH! have you heard--but of course you have--
Of a curious creature, as stubborn as brave,
An iron-heeled kicker, a buck-jumping knave,
      Called the Irrepressible Donkey?

The "Blondin Donkey" is full of his tricks,
But the Irrepressible easily licks
His Music-Hall model in capers and kicks;
And the cleverest rider is found in a fix,
When he sidles up to the animal's side,
Flings o'er the saddle his legs astride,
And rides, or rather essays to ride,
   The Irrepressible Donkey.
    [refrain]See him straddle, behold him rear!
    The cleverest rider may well feel fear,
    And cling to the neck; or hold on by the ear,
    Of the Irrepressible Donkey.

This mischievous "moke" is an awkward brute,
And apt from the saddle to suddenly shoot
The would-be Balaam who doesn't suit
    The Irrepressible Donkey.
Many a Balaam that seat hath had,
Riders good, and riders bad,
But Tory, Liberal, Whig, or Rad,
This dreadful donkey has driven them mad.
FORSTER fuzzy, and BALFOUR tall,
HICKS-BEACH, MORLEY, each and all,
At one time or other, have had a fall
    From the Irrepressible Donkey.
       [refrain]

BALFOUR mounted as well as most,
And some of his friends are beginning to boast
That he's a right RARERY, who will not be tost
    From the Irrepressible Donkey
Of Donkey-riding he has the gift,
Is up to each asinine struggle and shift,
Can make the animal feel his heft,
And prone on his back will never be left,
BALFOUR, they say, is a blessed boon,
He'll treat as the Colonel treated the coon,
And make dance, soon, to a genteel tune,
    The Irrepressible Donkey.
    [refrain]

Well, that, of course, remains to be seen;
At present the creature is prancing, I ween;
There still seems some "devil," and plenty of spleen.
    In the Irrepressible Donkey.
Round he goes with his hoofs asprawl,
His mouth gapes wide, and his teeth aren't small,
With his ears laid back, and his tail to the wall,
He doesn't appear a nice "mount" at all.
To brave BALFOUR and his "resolute" Chief
'Twill be a great joy, and a real relief,
To find there's one rider does not come to grief
    With the Irrepressible Donkey.
    [refrain] See him straddle, and stamp, and rear!
    Look at his grinders, and twig his ear!
    He'll still want a good deal of "riding," I fear--
    The Irrepressible Donkey!

Funny that the scansion of "Cannibal Islands" matches versions of "Donkey Riding." And what are the odds that the parody would have a similar "donkey" refrain-phrase? I can't imagine this one-off in Punch catching on, much less among sailors, so perhaps it's just a funny coincidence, but I think it is interesting.